Difference of Fine Root Nutrients and Stoichiometric Characteristics Between Castanopsis carlesii Secondary Forest and Natural Forest in Subtropical China

Abstract:

In order to understand the effects of human disturbance on forest nutrient utilization and biogeo-chemical cycling, the stoichiometric characteristics of fine roots in Castanopsis carlesii secondary forest and natural forest and their variation trend with soil depth (0-80 cm) were studied. The results showed that the main effect of stand and soil depth on fine root stoichiometry was significant by mixed linear model, but the interaction effect was not significant. The contents of N and P in fine roots of secondary forest were significantly lower than those in natural forest, while the C content, C:N and C:P in fine roots were significantly higher than those in natural forest. The C content of fine root at 1-2 mm diameter in secondary forest was significantly higher than that of natural forest. Fine root The N and P contents of fine root in natural and secondary forest decreased significantly with the increase of soil depth, while C:N, C:P, N:P increased with the increase of soil depth, and the change trend of root stoichiometric characteristics with soil layer were similar between secondary forest and natural forest. The contents of N, P and N:P in fine roots of natural and secondary forests were linear with the contents of total N, total P and N:P in soil, respectively. The contents of N, P and N:P in fine roots were significantly correlated with the soil depth, but not with the specific root length (SRL). Therefore, the stoichio-metric characteristics of fine roots did not change with soil depth in the natural forest after human disturbance, but the concentrations of N and P in fine roots decreased significantly.

Key words:Secondary forest;Castanopsis carlesii;Natural forest;Fine root;Stoichiometry character